Li Zhen,Chen Yingying,Lang Haoze,Wan Jianghong,Gao Yan,Dong Haitao,Zhang Xiaoke,Feng Wenran
The ternary Pb–SnSe thin films were prepared using chemical bath deposition (CBD) and sensitized with iodine. The chemical formula of the films was recognized as Pb 0.8 Sn 0.2 Se, according to the stoichiometric ratio. The films are both centered cubic crystal structure and show preferred orientation in PbSe (200). The optical band gap ( E g ) is found to decrease after sensitization, due to the impurity energy levels created by PbI 2 . The photoelectric performance of the Pb 0.8 Sn 0.2 Se thin films is significantly improved after iodine sensitization. Accordingly, the resistance change rate, i.e., the photoelectric sensitivity is enhanced over 35%, which is over 161% for more than 4 on/off cycles. The density of states (DOS) of Pb 0.8 Sn 0.2 Se is calculated using the first-principle method. The calculation shows that the I dangling bond in sensitized Pb 0.8 Sn 0.2 Se introduces a large DOS inside the band gap and causes the narrowing of the band gap.
Silu Peng,Haojie Li,Chaoyi Zhang,Jiayue Han,Xingchao Zhang,Hongxi Zhou,Xianchao Liu,Jun Wang
In recent years, lead selenide (PbSe) has gained considerable attention for its potential applications in optoelectronic devices. However, there are still some challenges in realizing mid-infrared detection applications with single PbSe film at room temperature. In this paper, we use a chemical bath deposition method to deposit PbSe thin films by varying deposition time. The effects of the deposition time on the structure, morphology, and optical absorption of the deposited PbSe films were investigated by x-ray diffraction, scanning electron microscopy, and infrared spectrometer. In addition, in order to activate the mid-infrared detection capability of PbSe, we explored its application in infrared photodetection by improving its crystalline quality and photoconductivity and reducing tge noise and high dark current of PbSe thin films through subsequent iodine treatment. The iodine sensitization PbSe film showed superior photoelectric properties compared to the untreated sample, which exhibited the maximum of responsiveness, which is 30.27 A/W at 808 nm, and activated its detection ability in the mid-infrared (5000 nm) by introducing PbI2, increasing the barrier height of the crystallite boundary and carrier lifetimes. This facile synthesis strategy and the sensitization treatment process provide a potential experimental scheme for the simple, rapid, low-cost, and efficient fabrication of large-area infrared PbSe devices.Keywords:chemical bath deposition;PbSe;iodine sensitization;photodetector
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